The man the Independent called "a thumping bore" and the Observer reckoned was "the most tedious artist in the Turner show" is signing autographs for besotted fans. It's 10.30am in the coffee bar outside the Turner prize exhibition at Tate Britain - the morning after the night that made Simon Starling £25,000 richer and unleashed a media furore about conceptual art, as well as abstruse meditations on the role of the shed (of which more later).

No matter that Starling makes work that is, according to one critic, as "dull as a sixth-form geography project". (When, incidentally, did geography projects become inherently dull?) Bearded and bespectacled, wearing a crumpled tweed jacket that one might well associate with a geography master and wearing a hat to conceal his self-confessed bad hair day, Starling hardly looks the winner of the sexiest, most media-friendly, sponsorship-rich art prize in the world. He isn't as flamboyant as Grayson Perry, nor as laddishly media-savvy as Damien Hirst, nor as controversial as Chris Ofili. But still.

"Congratulations," says a teenage boy. "Very impressive shed. I think what you do is great." His friend, a teenage girl, adds: "I really loved that thing you did with the bike." Starling obligingly signs their tickets and they retreat, beaming.

Do you like this kind of hoopla - the fans, the cameras, the face time with Matthew Collings and Nicholas Serota? "It's nice - for a moment," he says. "Usually my audiences are so tiny and so well informed that this is a bit -" he pauses. Odd? Terrifyingly philistine and vulgar? Flattering? His eyes sparkle by way of answer. "I'm flying back to Berlin this afternoon," he says with an evident sense of relief. "Back to the studio." It's the same sort of relief that I detected last year when I interviewed 2004 Turner winner Jeremy Deller. Instead of championing psychically troubled media monsters of BritArt, Turner judges now seem keen to celebrate articulate but delicate artists who take the money charmingly, do the media politely and then turn off their mobiles and retreat to their studios.

Starling doesn't sound the part either. He tells me about his thwarted dream to create a floating island of rhododendrons in the middle of Loch Lomond. It was to be a conceptual art project that commented on notions of migration, sanctuary and imprisonment. "You see, the rhododendron ponticum is regarded as the scourge of Scotland. It was originally from southern Spain, but was imported, I think, by a Swedish botanist. It was planted in gardens and then spread until it became a real problem. A lot of money has been spent trying to eradicate it from Scotland.

"Originally, I drove to Spain with seven of these plants and planted them with their ancestors." But the idea, like the rhododendrons, grew uncontrollably. "I decided I wanted to grow them in Loch Lomond in a thing called Island of Weeds. One of the funders was going to be Scottish National Heritage. Then someone realised that Scottish National Heritage had spent £5m trying to eradicate the rhododendrons, so it seemed to be a bad idea for them to fund a project that involved growing more. It became this whole political thing and it didn't happen."

Instead, he took a model of the project to the Venice Biennale three years ago. He says he is disappointed that there is no real Island of Weeds. But isn't a model good enough for a conceptual artist? Isn't the commodification of the concept in a final work just so much bourgeois hokum and not very interesting? Indeed, the charge against Starling is that the story of creating his work is more aesthetically important than the finished article. Guardian art critic Adrian Searle contended: "Back-story is everything in Simon Starling's work."

Consider Starling's prize-winning exhibit Shedboatshed (Mobile Architecture No 2). He was cycling along the Rhine when he came across a shed. He chatted up the owners who let him convert it to a boat, paddle it to Basel, rebuild it and then put it in a gallery.

"I was looking for something that I could use for a river-based project and, being lucky, I found it. The shed even had a paddle attached! And the owners were really happy with what I wanted to do. What I'm doing is just adding another layer to its history. It used to be a guard hut on the Swiss border." A fascinating back-story, no doubt, but unless you know all this then what you see in the gallery is just a shed. The Daily Telegraph suggested that this typified a problem in British art, namely: "None of it makes any sense until you are told what it is about." Until you get the Acoustiguide telling you that Shedboatshed "has a wonderful, absurd circularity in its exploration of our relationship with time and space", you might well compare it unfavourably with a flatpack from Argos.

Starling disagrees vehemently. "Some people will come to the work with a lot of knowledge, some not. That's true of any work of art. That's as true of a painting by Titian as it is of any conceptual work." I'm not sure this parallel works: Titian could legitimately have expected his audience to have had the biblical learning to understand, say, Noli Me Tangere, but surely Starling could not expect Tate visitors to know about his paddle down the Rhine. And sheds are over, artwise, aren't they? In 1991, Cornelia Parker filled one with junk, got it blown up by the army and exhibited the results under the title Cold Dark Matter: An Exploded View. Tracey Emin exhibited a beach hut and Mike Nelson had a bunker buried under a sand dune.

That said, Shedboatshed at least silences those who moan that modern artists have no skills. Who among tabloid blowhards or those Stuckists who annually rail against the dearth of painting in the Turner prize could put a shed together and convert it into a serviceable boat?

Is what you make art, I ask Simon Starling? "Maybe it isn't," he says disarmingly. "It's art because I trained as an artist." What, then, is the point of being an artist? "Art for me is a free space to explore things. The things I do don't always come out looking like conventional works of art. But then I'm like any artist these days working in relation to a long history of art. I think the press is a long way behind understanding this or responding to art in a sympathetic way. I got a lovely poem from a lady in St Albans about sheds."

Starling was born in Epsom in 1967, was educated in Sevenoaks, and did a photography degree at Trent Polytechnic before going on to study fine art at Glasgow. "I knew early on that I didn't want to study in London. I wanted to find something else, and Glasgow was the place. The early 1990s was a great moment for the city, there was a lot of buzz about the place." He currently divides his time between Glasgow and Berlin. Was London never attractive, career development-wise? "I'm not a big city person. I like to think things through at my own speed." Why Berlin? "I moved there for love." And stayed because it's an artistic hub? "Kind of." His partner is a writer and curator, and his son Vincent is 11 months old.

Starling's desire to make things that may or may not be art has flourished. Another of his prize-winning exhibits, Tabernas Desert Run, involved him making an improvised hydrogen-fuelled bicycle, riding across the Spanish desert on it and then painting a botanical watercolour of a cactus using the bicycle's only waste product: water. This eco-concept project appealed to the Turner judges, who liked how "he transforms and reframes existing objects using a rigorous process of research" and admired his "unique ability to create poetic narratives which draw together a wide range of cultural, political and historical narratives".

Starling will continue creating such narratives. He will spend some of his Turner winnings on placing a replica of Henry Moore's Warrior with a Shield sculpture in Lake Ontario and growing zebra mussels on it for six months, before exhibiting the results. He is also planning to rebuild the racing car that Turin-based soft-porn photographer and furniture designer Carlo Mollino once created for the Le Mans 24 Hour race. "It was this incredibly light car with a small engine, but it crashed after two hours because it was too light." The idea is to build a replica and drive it around Turin's ring road for 24 hours.

"It could be fun," he says, "on one level." On one level, it could be.

· The Turner prize show, sponsored by Gordon's, is at Tate Britain, London SW1, until January 22. Details: 020-7887 8888